/Engine/Source/Runtime/Engine/Public/MaterialCompiler.h
virtual int32 StrataAddParameterBlending ( int32 A, int32 B, int32 AMixWeight, const [FString](API\Runtime\Core\Containers\FString) & SharedLocalBasisIndexMacro, [FStrataOperator](API\Runtime\Engine\Rendering\FStrataOperator) * PromoteToOperator )